Contribution of mevalonate and methylerythritol phosphate pathways to polyisoprenoid biosynthesis in the rubber-producing plant Eucommia ulmoides oliver

The biosynthetic origin of isopentenyl diphosphate in the polyisoprenoid biosynthesis of the rubber-producing plant Eucommia ulmoides Oliver was elucidated for the first time by feeding experiments using ¹³C-labeled isotopomers of (RS) mevalonate, 1-deoxy-D-xylulose- 3,4,5-triacetate, 2C-methyl-D-erythritol-1,2,3,4-tetraacetate, and pyruvate. After ¹³C-labeled isotopomers were fed to the young seedlings, the polyisoprenoid fractions were prepared and analyzed by ¹³CNMR. The NMR data showed that the isoprene units of polyisoprenoid derived from isopentenyl diphosphate, which was biosynthesized using both mevalonate and 1-deoxy-D-xylulose-5-phosphate in E. ulmoides. It is assumed that the cross-talk of isopentenyl diphosphate, derived from both pathways, occurs during the biosynthesis of polyisoprenoid; therefore, it was observed in the formation of low-molecular weight isoprenoids.